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Security and Communication Networks
Volume 2017 (2017), Article ID 5454768, 13 pages
Research Article

Optimization of a Blind Speech Watermarking Technique against Amplitude Scaling

1Department of Computer Engineering, Islamic Azad University, Safadasht Branch, Tehran, Iran
2Cybersecurity Laboratory, National Electronics and Computer Technology Center, 112 Phahonyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand
3Department of Electronics Engineering, Universidad Autónoma de Zacatecas, 98000 Zacatecas, DF, Mexico

Correspondence should be addressed to Chalee Vorakulpipat

Received 31 August 2016; Revised 26 November 2016; Accepted 18 December 2016; Published 20 February 2017

Academic Editor: Emanuele Maiorana

Copyright © 2017 Mohammad Ali Nematollahi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper presents a gain invariant speech watermarking technique based on quantization of the Lp-norm. In this scheme, first, the original speech signal is divided into different frames. Second, each frame is divided into two vectors based on odd and even indices. Third, quantization index modulation (QIM) is used to embed the watermark bits into the ratio of the Lp-norm between the odd and even indices. Finally, the Lagrange optimization technique is applied to minimize the embedding distortion. By applying a statistical analytical approach, the embedding distortion and error probability are estimated. Experimental results not only confirm the accuracy of the driven statistical analytical approach but also prove the robustness of the proposed technique against common signal processing attacks.